1. Field of the Invention
This invention relates to a plug valve and, more particularly, to a top locking rotary plug valve, especially one with a closed bottom, which may be locked in a predetermined position. Valves of the class here contemplated find application in gas service lines, for example, to enable gas service to be shut off by locking the valve in its closed position. By the expression "top locking plug valve" I mean a plug valve lockable by the application of a security mechanism to the end of the plug at the open end of the valve body.
2. Description of the Prior Art
It is known from U.S. Pat. No. 2,092,572 directed to a concealed valve and lock plug, to provide a base 32 threaded into the upper extremity of an upstanding portion 19 of a plug casing and centrally recessed to provide a non-circular socket 71 that receives a pin 72 having a central cylindrical bore 73 adapted to receive an expanding tool or key of the type shown in FIG. 9. A cap 69 having a central bore 74 aligned with the bore 73 also has a non-circular socket 75 adapted also to receive the end of the pin 72. However, the pin is of a length to fit entirely within the lower socket 71 in the base 72.
The cap 69 has an interior groove 70 and the base 32 has an external groove 67 in register therewith so that both grooves may receive a washer that permits the cap to rotate freely relative to the base 32. A bore 74 in the cap 69 registers with the bore 73 so that when the key is inserted through the bore 74 into the recess 73, the non-circular sockets may be aligned and the pin 72 drawn upward so that it extends into both sockets 75 and 71 whereupon, a tool applied to the cap 69 to rotate the same will also rotate the base 32 thus permitting it to be removed from the casing of the valve, following which a suitable tool may be applied to the "operator" atop the valve plug in order to rotate the same.
A suitable tool is illustrated in FIG. 4 and includes a bushing 25 threadably receiveable into the upstanding portion of the casing and being centrally bored to receive the shank 21 of the tool, a spring 24 acting against the bushing and a sleeve 22 pinned to the shank so that when the tool is in use, the spring force is transmitted to the top of the plug in order to assure that it is held securely in the tapered bore thus to prevent fluid leakage while the plug is being operated.
U.S. Pat. No. 753,349 illustrates a lockable faucet utilizing a conventional lock cylinder operated by the placement of tumblers by a bitted key 16, the lock plug 3 being provided with a recess 9 engageable by a projection 10 integral with a lock-shell 11 which is rotatable by handle 26 in the cylindrical barrel 12 when the lock bolt 15 (FIG. 2) is retracted from the bolt-slot 14 (FIG. 4) by operation of the key.
U.S. Pat. No. 1,970,463 discloses a valve lock having a casing and plug, the upper end of the plug being recessed to receive a spring 17. The lock case 16 is preferably angular in cross section so that its sides may be engaged by a wrench for turning the same. The device includes a locking pin 19 which may project into annular channel 20 in the inner surface of the valve casing near its upper end or in an aperture 21 below the channel 20. When the valve case is depressed against the force of the spring 17, the pin may be projected into the aperture 15 to lock the device against rotation. That is, when the key is manipulated to retract the pin from the position shown in FIG. 3, the lock case may be pressed inwardly until it is seated in the valve plug in which position the pin is in alignment with the aperture 15. By rotating the key, the pin 19 is withdrawn from the aperture 15, the spring 17 projects the lock case upwardly and the pin may again be projected into the aperture 14 of the plug extension and into the annular channel 20 so that the plug may be rotated by application of the tool to the exterior side of the projecting lock case.
In U.S. Pat. No. 4,362,035, there is disclosed a lockable closure wherein, in order to permit disengagement of a threaded element from a conduit, a cam 72 is actuated by a key to permit movement of the lock elements 70 to their respective retracted position so that the lock pin 58 may slide axially outwardly from the bore 26. The shield 36 may thus be removed from the threaded element 20 in order to expose the flats 32 of the boss 30. A wrench may then be engaged with the flats and threaded element 20 may be unscrewed from the conduit 100.
In the second embodiment, as seen in FIG. 11, hexagonal section 151 is received in a mating socket formed in cap element 146. The shield 144 is provided with a cylindrical recess 152, as shown in FIG. 10, coaxially surrounding the stem 150 over a portion of its length and a radially inwardly facing annular groove 153 in the circumferencial wall of the recess. The face 154, transverse to the axis of the stem 150 is provided on flange 148, recess 152 being open to the face 154. Crown surface 180 of lobe 176 confronts a lug 196 and surface 182 of lobe 178 confronts the other lug 196 when the cam 168 is in its engaged position. Upon rotation of the shield 144, and hence of the stem 150, each lug 196 will encounter one of the ramp surfaces 140 or 142 of the groove in which it is engaged and each lug will thus be urged radially inwardly. However, the lugs will bear on one of the crown surfaces of the cam and will therefore be retained in engagement in one of the grooves 138, and also in one of the openings 164 of the stem, the lugs will connect the stem and hence the entire shield to the threaded element for rotation therewith in either direction. Accordingly, the threaded element 120 can be unscrewed from the conduit 100 or tightened on the same.
Other disclosures of interest will be found in U.S. Pat. Nos. 1,541,216, 2,059,085, 4,024,740, 4,458,510, 4,465,092 and 4,483,366.